The Reserve Bank research, published on Thursday, also revealed online banking and fast money transfers were by far the most likely to suffer technical problems, and outages on Mondays were taking longer to fix.
Financial experts said while the report showed the reliability of Australian services compared well to other nations, consumers' growing reliance on digital payments and banking meant any outage could have significant consequences.
The report comes one day after a string of outages hit Westpac and subsidiaries including St George, Bank of Melbourne and BankSA, leaving customers unable to access their accounts online.
The Reliability of Retail Payment Services was based on incident reports issued to the Reserve Bank from payment providers dating back to 2012, and more detailed statistics starting in 2021.
The data detailed significant financial outages lasting longer than 30 minutes.
Researchers Jared Griffiths and Matthew Joyce found the number of financial outages in Australia had dropped over the period, with a steep fall during the first three months of 2024.
But the duration of financial outages had not fallen, with the median length of incidents involving fast money transfers and ATMs lasting more than two hours, and next-day transfer outages taking almost eight hours to resolve.
Online banking and fast money transfers experienced the greatest number of outages, and the biggest causes of technical issues were problems with third parties and technology platforms.
Curiously, researchers also found incidents discovered on business days took longer to resolve, with incidents on Mondays taking the most time as system changes were commonly undertaken on weekends.
"Every incident or outage can potentially cause inconvenience or economic harm for end-users of those systems," the report noted.
"Given the wide-reaching impact of outages, the effective management of operational risk in the payments system has never been more important."
Consumers' reliance on contactless payments and digital banking had increased during the COVID-19 pandemic, RMIT finance senior lecturer Dr My Nguyen said, giving any outage a stronger impact.
Companies moving into fintech products, such as Chemist Warehouse that announced plans offer QR codes for money transfers, would need to pay close attention to their software, security policies, and relationship with third party providers, she said.
Despite longer than expected disruptions, Dr Nguyen said Australia digital payment technology, at 99.8 per cent availability, compared well on a world scale.
"In terms of global trends, Australia is doing fairly well for reliability," Dr Nguyen told AAP.
"In the US, 15 major outages were reported in 2023 and the majority were due to cyber incidents."
